Switch and signal control system for railroads



N. B. COLEY Dec. 9,v 1941. 2,265,350

' swmcnjmn SIGNAL CONTROL SYSTEM FOR RAILROADS Filed May 8, 1959 8 Sheets-Sheet l ATTORNEY Dec. '9, 1941. N. B. COLEY 2,265,350

SWITCH'I'AND SIGNAL CONTROL SYSTEM FOR RAILROADS Filed May a, 1959' a Sheets-Shet 2 an 3T F E6 v 3 u 1.1HI3 @Y J n 96 U R N nzm em 8 f 1 ru as ea 5 VM/ n. 51% m d m N}- B. COLEY SWITCH AND SIGNAL CONTROL SYSTEM FOR RAILROADS 8 Sheets-Sheet 3 Filed May 8', 1939 INVENTO ATTORNEY Dec. 9, 1941. N, B, com 2,265,350

SWITCH AND SIGNAL CONTROL SYSTEM FOR RAILROADS f Fil ed May 8, 1959 a Sheets-Sheet 4 INVVENTOR N. B. COLEY SWITCHLAND SIGNAL CONTROL SYSTEM FOR RAILROADS s Sheets-Sheefi 5 Fil ed May 8, 1959 ATTORNEY Dec. 9, 1941. N. B. COLEY 2,265,350

SWITCH AND SIGNAL CONTROL SYSTEM FOR RAILROADS 224 3Q p 218 I 2512 6 212? +3 207 U m: ASWE I 213" 214 5} I a Z 2sm.@' 215 H am N. B. COLEY Dec. 9, 1941.

SWITCH AND SIGNAL CONTROL SYSTEM FOR RAILROAD-3 a Sheet-Sheet 7 Filed May 8, 1939 IBQWE 6995 AIQWE BIORE DqwE F821:

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'AiOR E N. B. COLEY Dec. 9, 1941.

SWITCH AND SIGNAL CONTROL SYSTEM FOR RAILROADS 8 Sheets-Sheet 8 ii Z BY h-Mn Filed May 8, 1939 Patented Dec. 9, 1941 FOR RAILROADS Nelson B. Coley,

Rochester; N; Y, assignor' to General Railway Signal Company, "Rochester; N

Application May 8, 1939, Serial No. 272,319

30 Claims.

This invention relates to switch and signal control systems for railroads, and it more particularly pertains to such systems of the entranceexit type which are characterized by the establishment of each route in the track layout in response to the designation by an operator of the opposite ends of that route. i

For designation of the route ends, push buttons, or other suitablecontactors, are provided on a control panel in a tower or control office within convenient reach of an, operator. In order that an operator can readily associate each buttonwith the particular route end for which it is provided, and for the purpose of facilitating the dispatching of trains throughthetracklayout, a miniature track diagram is provided on the con,- trol panel representative of the track layout in the field for which the system is provided, and the buttons are distributed along the track diagram at points representative of the signal locations which define the route ends with which those buttons are respectively associated. Indication means, such as indicator lamps, are usually provided along the miniature track diagram in order that an operator may be informed as to the routes established, the indications of the signals, and the condition of occupancy of the various track sections.

The usual manipulation by an operator in designating a route to be set up is to first designate the route end that is to be the entrance point in the route being set up, and to then designate the route end that isto be the exit point for that route. The sequence of operation of the buttons for the respective ends of each route can be used as a means for determining the direction for which the signals shall be cleared, or the direction can be determined by providing a button on the control panel for theentrance point at each signal location and a button on the control panel ,for the exit point at each signal location, thus requiring an operator to define the direction for which the signals are to be cleared,v by the kind of button he actuates, namely, an entrance or an exit button.

An object of the present invention is to provide,

by means of two circuit networks, a route select-J ing system by which normal and reverse switch control relays controlled by such networks select the desired position for each track switch included in each available route having its entrance andyexit ends designated by an operator, irrespective of the number of track switches includedbetween the route'endsdesignated.

" Another object of the present invention is to so 55 track switches trailed from select the control ,ofuthei normal and reverse switch control relays that either a normal ora reverseswitch control relay is picked up for each trailing track switch included in an. available route emanatin from a designated entrance point. I When optional routes are .involvedand a track switch can be trailed ,either normal in one route or reverse in another route emanating from a designated entrance point, the normal position of that track switch is generally selected by the picking up of its normal switch control relay in preference to its reverse switch control relay, When the circuits providesuch preference, and optional routes are involved, preference is given to the available route diverging nearest the designated entrancepoint, except when such diverging route is an inferior run-around route. Where interior run-around routes are involved, the most direct route is given preference by the system be, cause of the normal switch control relays having preference over the reverse switch control relays.

Another object of the present. invention is to prov dea means whereby, a particular route can be given preference over other optional routes between designated entrance and exit points, even if that route does not diverge via the crossover. nearest the designated entrance point. Such preference is oi'ten required in practice in order to prevent the unnecessary tying up of routes, or in order to cause a high speed track switch common to several routes. to be used when available in preference to lower speed track switches. To provide such mode of operation the reverse switch control relay is given preference over the normal switch contro relay, responsive to the designation of an entrance point, for the particular track switch that can select the desiredprererred route if operated to a reverse position.

Anotherobject 0-1 the present invention is to select the control of the normal and reverse switch control relays in the circuit networks in such a manner that either a normal or a reverse switch control relay is picked up for each track switch trailed .i'rom each designated exit point when a route is definitely selected'up to that track switch from the exit point designated. Such control of the switch control relays responsive to the designation of each exit point is accomplishedby use of thesame circuit networks that are used for energizing the normal and reverse switch control relays responsive to the designation of an entrance point. Thus, the same circuits that are used in picking up are used in picking up those normal and reverse normal and reverse relays for. each entrance point route which is completely selected after designation of the exit point, is inefiective to cause the positioning of the track switches with which those normal and reverse switch, controlrelaysare as sociated. Such mode of op :on" is'acc i r',1-v plished because the circuits provide that a track switch can be positioned, responsive torqute end designation by an operator, only-after a switch control relay has been picked up for that track;

switch dependent upon designation of an entrance point, and another switch control relay for that track-switch has been picked up "de- .pendent'upon the designationof the exit point for. that route. Thus, because the nature'of the system .is such. that switch" control relaysare picked unresponsive to the designation of the exit point, cnlyvto correspondwith the route to be selected, the track switches are positioned only they are included in the route actually selected. V r

. .Another object with respect to the execution oi the. switch controls in accordance with the rcuteiselectedi is to provide a difference in starting: time. oi th switch machine motorsfor the track switches included in each route selected in order to better distribute the power load; Such difference in starting time is provided-by the...cascade-. manner in which the switch control relays are picked up responsive tothe designa tion of theiexit point.- That is; responsive to the designation. of an exit point in setting upa route, theswitch control relays are picked up in succession, onelrelay or one-small: groupof relays at a. time, starting.;withthe relays for the track switch nearest the exit point designated;- and, because the. picking up. of each of thoserelays causes, the. operation of: the switch machine for that track switch, themotore are started successively, one motor. ononesmall group of motors at a.-time,.starting. with the; motor forthe track switch. nearest the. designated exitpoint.

. Having thus'pointedi out ina general manner someof the objects of thepresent invention, due to,the.complexity=of: the system, itis-believed that other. objects, purposes andcharacteristic features. of-the present-invention will be more thoroughly understoodfromreference tothe accompanying drawings and as they are pointed out hereinafter in the description of 1 the present invention. I

In describingthe invention. in detail; reference will: be madetothe accompanying drawings; inwhich like referencecharacters designate corresponding. parts throughout. the several illustra-.. tions, in, which similar. letter. reierenceicharacters are used to designate parts of. a. similar. general.

uch I; t ibeir een ra l maded stin r.

ffncg haracters representative. san whic 1 id l gwen nee n nesel e e in s uitaw-J n Pro.-

f z p m umera s or. by. are

mate nal. nd. r s ,t lars pr. heq rac s arout hcw 7 aj-end; muse Fig. 2 illustrates various switch and signal control circuits for a particular crossover as typical of the circuits provided for each of the crossovers included in the track layout for which the system is provided;

Fig. 3 illustrates the track layout for which the circuit networks illustrated in Figs. 1A and 1B are provided, together with the signal control circuits relative to, the control of th signals associated with that particular track layout;

Fig. 4, when placed end-to-end with Fig. 1A, illustrates how the circuit networks can be provided-1 to give preference to a particular given one or a plurality of optional routes; and

ig s, 5A; 515 when placed side by side, illustr earneans; o,; providing indications on the section of the track diagram illustrated in Figs. l A and 113. I

Fig; 6 illustrates the switch control for a particular single switch as typical of the circuits providedior each of the single track switches that rn-aybe i nc-luded in any' track layout for which the systein is provided.

parts of a siniilarorclassicy-use of the-ltter reference characters Ger-isms tosu'ch parts without their distinctive preceding; letters or nu rrierals Such a reference is to be understood to apply toany-partsdesigi iated in the drawings by letterreference characters that are similar ex- 'cept for preceding numerals; orpreceding letter reference characters characteristic ofithe various signs-1 locations;

In order to simple asmuch as possible, the dfsclcsure of the present invention, various diag graniinatie and conventional illustrationshave been employed in the-drawingsfor-the purpose of facilitating the disclosure or the present inventic'ria-s to th'ep'rinc-iple's involvedand themode of operation; rather than for showingthe specific ccns-t'r'uctionand arrangement of parts that would; be employed practice, Thus, the varinus-relays and their-contacts are shown inacon- Venn-mar manner; certain circuit; details thos familiar-with the artare merely indicated eydotted lines, andsymbols are used to indicate the connections to the terminals; of batteries; or othersourcesofj electric current instead or: showing all arthe wiring connections-tn such terminals; 'I'he s'y'rnbolsand are-employed to dica-te the positive and negative terminals respectively as suitable: batteries or: other sources; of current, and the circuitswith which. those symbols are-usedfalways=have=current flow v mg inthesame-direction. I falternating current is-used instead oidirect-current, thesyni'bols are tobeconsider-ed Iasrepresentativeoi? the instanta-Ilecus relative pola rities.

tr'a'cklayout for this parti'cfulae embodiment at the present invention is iilu'sitrated -infwhlch two parallel tracks-are connected by rossovers-mving the track switches ZTSB, 4'I SA and 455813, andithelower on ioiztii'eitw-o-parallel tr acks is-iHustr-ated: as .being: connected to. a third? traclr bythetrach switch 321B; tubes; s p sitioned: by; a

required in practic with respect to their control, such as over-load protection, such, for example, as is shown in the patent to W. H. Hoppe et al., Patent No. 1,877,876, dated September 20, 1932.

Inasmuch as the track switches for each end of a crossover are generally positioned in correspondence with each other,.for the purpose of simplifying the present disclosure, only one switch machine has been shown for the .positioning of the track switches for both' ends of each crossover, however, it is to be understood that a separate switch machine can be provided for each end of each crossover in accordance with the requirements of practice. Thus, switch machine 25M is provided for positioning track switches ETSA and 2TSB,.switch machine 38M is provided for positioning'track switch 3TS and switch machine lSM is provided for positioning track switches QTSAand 4TSB.

The locked position of each of the track switches in correspondence with the lock position of the corresponding switch machine is repeated in the usual manner by a polar neutral relay WP.- Each of the relays WP is assumed to be energized with its polar contacts operated to a right hand position when the track switches with which it isassociated are in correspondence with the normal locked position of the switch machine SM, and each relay WP is energized with its polar contacts operated to a left hand position when the associated track switches and switch machine are both in a reverse locked position. Whenever the switch points and/or the switch machine are unlocked the relay WP associated therewith is deenergized.

For the purpose of selecting such control for each of the relays WP, point detector contact mechanisms are provided of the type shown, for example, in the patent to C. S. Bushnell, Patent No. 1,517,236, dated November 25, 1924.

Signals are provided for governing trafiic through the track layout in both directions, signals A and B having been provided for governing east bound trafiic to the right through the track layout illustrated in Fig. 3, and signals C, 'D and E having been provided for governing west bound trafiic to the left through that track layout.

The signals have been illustrated as being of the color light type having individual color lamp units, the upper lamp unit providing a green clear indication, and the lower lamp unit providing a red danger indication. It is to be understood that additional indications, such, for example, as a yellow indication for caution can be provided in accordance with the requirements of practice, and that other types of signals such as search light and semaphore signals can be used.

The track layout illustrated in Fig. 3, is shown as having been divided into track sections by the usual insulated joints, and it is to be understood that the usual type of track circuits are provided for each of the sections. Track sections 1T, 8T, QT and MT have been illustrated as having been provided for the control of track relays 'ITR,

8TB, 9TB and lOTR respectively. It is to be understood that the track switches are properly bonded to provide the usual fouling protection.

Control machine.-A principal part of the con trol machine for governing traffic through the track layout is a control panel within convenient reach of an operator upon which is constructed a a miniature track diagram of the track layout for which the system is provided. Thus, for this embodiment ofthe,presentinvention, the track 7 diagram illustrated at the top of Figs. 1A and 1B is illustrative of the track layout shown in Fig. 3. Suitable indicator lamps are provided along the miniature track diagram in order that an operator can be well informed as to the condition of occupancy of the track sections, the indications displayed by the various signals, and the routes which are established through the interlockingplant. The lamps (see Figs. 5A and 5B) are assumed to be mounted on the back of'the panel behind translucent strips of which the track diagram is constructed. For the purpose of limiting the light from each of the lamps to the particular portion of the track diagram with which that lamp is associated, suitable baflies 216, or the like, are provided at the limits of each of the portions associated with each of the lamps.

A control button NB (see Figs. 1A and 1B) is provided on the miniature track diagram at a point representative of the entrance point to each route, and a control button XB is provided on the miniature track diagram at a point representative of the exit point to each route. Thus, because trafiic is provided in both directions in the present embodiment of the invention through the track layout, each of the route ends has asso: ciated therewith an entrance button NB and an exit button XB. Inasmuch as the route ends are determined by the location of the signals, the buttons ANB and AXIB (see Fig. 1A) are provided on the miniature track diagram at a relative position to the signal A for the corresponding route end at the track layout. Thus, in a similar manner, an entrance button NB and an exit button XB is provided for each of the signal locations. 7

Each of the entrance buttons NB is of the push-pull type, and is biased to a center position from which it can either be depressed or pulled out. Each button NB is provided with a normally closed contact which is maintained closed when the button is depressed, and another contact which is closed only when the button is in a depressed position. The construction of the button to provide such a contact arrangement can be provided in a manner shown, for example, in the prior application of'J. F. Merkel, Ser. No. 158,720, filed August 12, 1937. Each of the exit buttons XB is of the self-restoring push-button type having a contact closed only when the button is depressed.

Although separate buttons have been shown in this embodiment of the invention for designation of entrance and exit points, it is to be understood that a single button could as well be employed for each of the route ends, having distinctive positions for designation of entrance and exit points for that route end. It is also to be understoodthat a single push button could as well be employed for designation of both entrance and exit points if means is provided, such as by sequence of operation of the buttons, for designation of entrance and exit points, for determining the direction in setting uproutes, such as is shown, for example, in the prior application of N. D. Preston, Ser. No. 183,499, filed January 5, 1938. v

An auxiliary switch control lever SML is provided for each of the crossovers andfor each single trackswitch in order that an operator may have individual control of each crossover and each single track switch for use in setting up routes not provided by the self-selecting network,

and for use in freeing the; track switches from 1 4 obstruct-ions. such, for example; as snowand: ice.

System devicesl- Each of the entrance'points in the track" layouthas: associated therewith in the; controloflice' an entrance relay NR which is energized responsive to the desi'gnati'om of that particular entrance point by an operator, and which is maintained energizedi dependent-for deenergizationl upon thepassageof 'a train= past that 'entrancepoint, or dependent for deenergizationupon manual actuation: of the entrance button- NB for that particularentrance point-to a: distinctive position from that used for designation of such entrance point-in designating a route to besetup:

An-exit relay is'provided for-"the exit point for each sig-nal location; .andwach of such exit relays isresponsive tothe designation of an exit point in setting up a route by the depressiomof theex-itbutton XB'ior that particular route end. Each ex-itrelay-XE can to the designation-of an-ex-it point insetting up a route only if-La route is available between-that exit point andthe entrance point designated for that. route. When once picked up eachexit relay XR- is maintained energized dependent upon the picked up condition of the-entrance relay for the entrance-point to the corresponding route;

Relays AN; BN, N, BR and R a1'e-normal and reverse switch-controlrelays energized in the circuit networks responsive to the picking up of the entrance and exit relays NR, and KR respectively.- R-elays -BN and N a are provided for causing operation oftheir respective track switches to -normal-positions; and relays AR; BR and Pw areprovided for causing theoperati'om of their respective track switches to reverse-positions. The relays AN and for eachcrossover areassociatedwith the track switchesat the upperend -oi their respective crossovers and the reIays'BN- and' BR for each-crossover are asso ciatedwith the track switches at' the lower end of their respective crossovers.- That *is, for example (see Fig. '2) the-relays 2AM and ZAR are associated with track switch E T-SA; and the re-- lays ZBN- and Z'BRw-areassociated with track switch 2T-SB, The positioning of theatrack' switch foreither end or each crossoveri's, however; dependent upon-the picking-up of theAN or" AR relay, as: the case maybe,- -for 'oneend of the crossover and the- BN-or BR-"relay for the corresponding position for the oppositecnd -of the' crossover.

Relays N-- and R; are provided for-causing the"- operation of their respective single "traclrswitch to a respective normal or reverse position; suchpositioning ofthe track switch *being' effective-*- only when an execution relay X "associated with that singletracls switch is picked up;

With reference to-Fig;. 2; two lock relays L areprovided'for-eachcrossover; one-for the detector track section at each end ofthe crossover, for allowing the operation of-"the track switches for that crossover only at timeswhen such operation is-=safe and desirable. It isbelieved that it will be readily apparent that-only one lock relay is required foreach-singletrackswitch, and'it-isalso to be understood that, when one detector track. section is common toa number- 0f track switches, :only: one lock relaw L' associated with thatydetector track. section= Will -be required for the, group of: track: switches; dependentmpon the requirements: of (practices '.'Ihat1.'is;.one .lock reelay L.. can be: provided: per track; circuit;..:or:'one. track:

10.01::- relay E ,.can:. be provided'itpen bepicked up responsive azcsgssc switch andtwo lock relays per-crossover. For thisembodi'm-entof, the present invention one lock relay Ii. isprovided persinglef'trackswitch and two lockrelays are provided per crossover.

A polar neutral relay WZ is providedfor each of the crossovers and each single track" switch in accordance with the circuits shown as typical in Fig: 2'. Each relay WZ is responsive to the normal and reverse switch control relays, and when energize'dcauses theoperati'on of the switch machine forthe associated track switch. Each of the relays WZ provides a-means by which each track switch. will complete, its. operationv when such. operation has been initiated, irrespective of the restoration to normaliof the normal and reverse switch control relays, andlit also provides a means by which reversal of a switch machine in mid'st'roke can be effected; as issometimes requiredwhen obstructionsprevent. acompletion of the. operation. to. the desired position.

For repeatingthelocked positionof. the track switches in correspondencewith the switch controls. selecte d; normaland reverse, correspondence relaysiNCRandlRCR respectively areprovided,

With reference. to Fig- 3,, a signal .control relay G. isprovided' for governing the indication displayed" by eachsignal; When a. signal. control rel'ay G is in a dropped away position the corresponding signal displays, a. red danger indication, and'whena signaLrelayG. ispicked up, the cor responding. signal. displays; a. green clear indication.

Having. thusconsidered, the. general. organization of' the apparatus. in accordance. with. the presentinvention, .cons'idera-tiomwill.nowbe given more. particularly to. the-mode. of. operation of. the system and. the; principles involved.

Operation 1 route in which they, were, last included. Thus.

so under the conditions. assumed. as. normal in.the.

present disclosure, the. track switches-are assumed to. he, in the. normalgpositions. last. required for through routes ,on .theltwo parallel tracks.

Under, normal conditions the relays .areall .deenergized; ,as illustrated.. in the accompanying. drawings .except the track relays TR (seeFigQZ), the switch repeater relays WP, the lock relays L, andthe route lockingrelay-s ESand-WS. The track.v relays TRand thesswitchr repeater. relays-- WE-are;normally;energized by circuits Well-known; to. those; familiar with! the. art; and the flock relays; for each; track. switch: are; energized'ingaccordance; with: the; typical circuitsf shown inEig; 2. for; the =lock;relays:1l i and 8L associated with: the track switches;2'.=IS-A.,andj2TSB.. Relay-TL. is normally. maintained. energized. by .a: circuit closed from :(-+).,;through a. circuit. including. front contact 20 of: relay; lWS,.front-contact 2i Ofy1'e1ay ="TTR, front contact: 22. Off relay' lES, windingnof; relay 'lL' and frontzcontact: 2 3 a ofirelay; IL,. to: .iRelay-BL isnormally; mains tained;:energizedQbyaas. circuit: closed IIYOmL through; a2 circuit? including front'lcontact l'li off relay1 8WS, ironticontact :'25'- or:' relay 81R;.- front3 contact 26 of relay 8E5, winding of relay 8L, and front contact 2! of relay 8L, to

The route locking relays ES and WS are normally energized directional stick relays that are controlled in a manner similar to that shown, for example, as in the patent to A. Langdon, Patent No. 2,148,865, dated February 28, 1939. If it is required in practice that approach locking be provided, the control of the relays ES and WS can include approach locking in a manner such as is shown, for example, in the patent to C. F. Stoltz, Patent No. 2,115,511, dated April 26, 1938.

Self-selecting netwrk.-As has already been pointed out in a general manner, the self-selecting network consists of two circuit networks. One of the networks is energized responsive to the designation of a route end at a particular end of the track layout as either an entrance or an eXit point, and the other circuit network is energized responsive to the designation of a route end at the opposite end of the track layout as either an entrance or an exit point. The designation of the exit and of a route is effective for energizing the circuit network responsive to the designation of that particular route end, only if a route is available between the designated entrance point and that exit point. Included in each circuit network is a normal and a reverse switch control relay for each track switch trailed from the route end from which that circuit network is energized. Thus, two normal and two reverse switch control relays are provided for each crossover,one normal and one reverse switch control relay being provided for the track switch at each end of the crossover. In addition to a normal and a reverse switch control relay provided for each single track switch, there is a relay X provided whichis responsive to the energization of the opposite circuit network from the circuit network in which the normal and reverse switch control relays for that track switch are energized. Such relay X is provided for a single track switch in order that switch controls for a single track switch is dependent upon designation of both entrance and exit points as is required in a route over a crossover.

To consider more specifically how the system provided by the present invention operates, consider, as a typical example, that an operator desires to set up a route fromsignal A to signal E (see Fig. 3) at a time when the normal conditionsof the system exist as they have been described.

The depression of button ANB as designation of the entrance point for such a route (see Fig. 1A) causes the picking up of the entrance relay ANR. When relay ANR is picked up a circuit is closed to cause the picking up of the reverse switch control relay 2BR because that track switch is trailed from the designated entrance point. exit relay EXR is picked up, and the picking up of that relay causes the picking up of relay-3R because the single track switch 3T8 is trailed from the exit point designated. After that reverse switch control relay is picked up, in accordance with the general principles of the system, namely, that the selection of each track switch to be included in a route is dependent upon both entrance and exit designation, a switch execution relay 3X is picked up to complete the selection of track switch 3TS as being definitely included in the route being selected. The energiexecution of the Upon designation of the exit point the closed from zation of relay 3X is dependent upon the picked up positions jointly of relays ANR. and 3R. After relay 3R is picked up the reverse switch control relay ZAR is picked up to complete the selection of the route, because that track switch is also trailed from the exit point designated.

Having thus outlined the general mode of operation in selecting a route from signal A to signal E, consideration will now be given in detail to the circuits involved in such selection. The depression of button ANB causes the picking up of the entrance relay ANB, for that particular entrance point, by the energization of a circuit through a circuit including contact 23 of button ANB closed in a depressed position, winding of relay ANB, and front contact 29 of relay TFTR, to When relay ANR is picked up, a stick circuit is closed for that relay from through a circuit including contact 28 of button ANB maintained closed in both a normal and a depressed position, front contact of relay ANR, winding of relay ANR, and front contact 29 of relay 'ITR, to Res-pom sive to the picking up of relay ANR, a switch control relay is picked up for each track switch trailed in an available route from that designated entrance point, thus, relay 2BR is picked up by the energization of a circuit closed from through a circuit including front contact SI of relay ANR, back contact 32 of relay AXR, back contact 33 of relay ZAN, back contact 34 of relay ZBN, and upper winding of relay 2BR, to Although energy feeds through the circuit network for switch control relays associated with crossover 4, to cause the energization of some of such relays, in order to confine the description as much as possible to the route assumed to be designated, reference will not be made to the energization of such switch control relays for cross- ZBN, back contact front contact to shunt of the circuit just described, such stick circuit over 4 at this time. I

Upon designation of the exit point for signal E by the depression of exit button EXBKsee Fig. 1B), the exit relay EXR is picked up by the energization of a circuit closed from through a circuit including front contact 3| of relay ANR, back contact 32 of relay AXR, back contact 33 of relay ZAN, back contact 3d of relay ZBN, front contact 35 of relay 2BR, back contact 36 of relay 3! of relay 3N, wire 49, winding of relay EXR, back contact 38 of relay ENR, and contact 39 of button EXB closed in a de, pressed position, to The picking up of relay EXR closes a stick circuit for that relay at contacts 38 and 39 out being provided in order to maintain relay EXR picked up after the exit button EXB is restored to normal, and to prevent the dropping away of relay EXR if an operator should depress button ENE, for any particular reason, to cause the picking up of relay ENR.

Responsive to the picking up of relay EXR, relay SR is picked up, because that track switch is trailed from the designated exit point, by the energization of a circuit closed from through a circuit including front contact 4| of relay EXR, wire 42, back contact 43 of relay 3N, and upper winding of relay SE, to

After relay SR is picked up, the execution relay 3X for that single track switch is picked up to cause the positioning of track switch 3 in accordance with the reverse control selected upon the picking up of relay 3R. Belay 3X is picked up by the energization of a circuit closedfrom through a circuit including front contact 3| of relay back contact-s2 ofrelay AXR, back contact 33 of relay ZAN, back contact 34of relay2BN, front contact 35 of relay 2BR, back contact 36of relay ZBN, front contact 44 of relay 3R; and winding of relay 3X, to

Th picking up of relay 3R also causes the picking up'of relay ZAR for the track switch at the upper end of crossover 2, because that track switch is trailed from the designated exit point, by the 'energization of a circuit closed from through a circuit including front contact 4| of relay EXR, wire 42, back contact 43 of relay 3N, front contact 45 of relay 3R; back contact 46 of relay 3N, back contact 41 of relay ZBN, back contact 48 of relay ZZAN, and upper winding of relay ZAR, to Upon the picking up of relay ZAR, the track switches of crossover ZR'are'operatedjto their reverse positions because the reverse relays ZAR and 2BR are both'picked up.

The specific means by which the track switches are actually operated, andthe means by which the signal is cleared for the entrance to the route, will be hereinafter considered.

From the above described circuits, it will be readily apparent that the exit relay EXR can be picked 1 only whenthere are no positions for track switches, included in the route between that exit point and the designated entrance point, which have their controls already selected by the picking up of thenormal switch control relay for operating. those track switches to a normal position.

"It will also be apparent from the circuits just described that energy can feed through the circuit network for the normal and reverse switch control relays only so far as there. are no conl c ina route between the track switches associated with such normal and reverse relays and the desighated-entrance point. That is, energy can be fed through the circuit network to relay ZAR only if the normal switch control relays {AN and ZBN forthat crossover are dropped away to close back contacts 48 and respectively; and onlyif relay 3N is. dropped away to close back c'ontact46,

When relay ZAR .is picked up, responsive to th'e'designation of the exit, point in setting up the'route. from signal A to signal E a branch of the circuit network for the control of track switches to the right of track switch ZTSA is openedat back contact 50 of relay ZAR to cause any' switch control relays energized by that branch of the circuit network to be dropped awa'y and, in a similar manner, the picking up of relay'3R opens the branch of the circuit network for the control of track switches to theright" of track switch 3 at back contact i4 to cause any switch control relays energized by the branch of the circuit networkextending to the right of that contact to be dropped away.

Upon the picking up of relay ZAR, responsive to the designation of the exit point, the branch ofv the circuit network'extending from front contact .58 of relay BNR'to the center winding of relay 2311 is opened at back contact 66 to prevent the energi zation of relay ZEN if an operator should designate an entrance point at signal B while the route is set up from signal A to signal E. Back contact- Hll of relay 2BR, connected in multiple with back contact 6! of relay EAR, is open atthat time because relay 2BR has been picked up responsive to the designation of the entrance point.

As an example of how the same circuits are used in selecting a route for both directions of positions of the-track switches in the an operator tosetup the same route for west bound traiiio as has been just described for east bound trafijc. Thus, when the normal conditionsof thesystem exist as has been described, assume an operator to designate a route to be set up from signal E to signal A. The depression ofbutton ENB for designation of the entrance point, causes relay ENR to be picked up, and a stick circuit tobe establishedfor'that relayby'th'e energlzation of circuits similar to those describedfor entrance relay ANR; Upon the picking up of relayENR, front con.- tact 530i relay ENR applies energy to the same circuit just described for relay 33 at back contact 4| of relay EXR. The energization of that circuit causes the picking up of relays 3R and EAR in a manner similar to that which has been described.

Upondesignation of the exit point for such route at signal A by the depression of'button AXR, relay AXR is picked up by the energization of a circuit closed from (-1-), through 'a circuit including front contact 53 of relay ENR, back contact 4! of relay EXR, wire 42, back contact 43 of'relay 3N, front contact 45'ofrelay 3R, back contact 46'of relay 3N, back contact 41 of relay ZBN, back contact 48' of relay ZAN; front contact 54 of relay 2AR, back contact 55 ofrelay ZAN, winding of relay AXR, back contact 5610f relay ANR, and contact 5'! of button AXB closed in a depressed position, to The picking up of relay AXR closes a stickcircuit for that relayv at front contact 58for'shunting contacts 56 and. 5'! out of the circuit just described.

When relay AXR' is picked up, the closing of front contact 32 causes energy to. be applied to the circuit that has been described'for relay 2BR, and, after relay 2BR is picked up to close front contact 35, relay 3X is picked up by energy applied at front contact 32 of relay AXR to the circuit which has also been described for that relay.

The picked up position of relays 2BR and 2AR jointly causes'the track switches of crossover Z to be operated to their reverse positions, and the picked up position of relays 3K and ER, jointly causes track switch 3TS to be operated to a reverse position.

. It will be noted that, although the circuitsfor the relays 2BR, 2AR,. 3K and 3B are common for both directions of traffic, the order in which the'track switches are definitely selected as being included in the route by the joint energization of a relay responsive to each of the two circuit networks, is dependent upon the direction of traffic designated by an operator. That is, in setting up a route from signal A to signal E, the track switch 3TS is selected first as being definitely included in the route by the joint picked up position of relays 3B and 3X, however, in setting up a route from signal E to signal A, the track switches 'of' crossover 2 are selected first 'as' being definitely included in the route by the Such feature is that, responsive to the designation of an entrance point, energy feeds through the circuit network in all directions corresponding to the routes available emanating from that point, while the designation of an exit point confines the energization of the switch control relays in the circuit network to one particular route. The designation of an entrance point at signal A in the example described above, by the picking up of relay ANR, causes energy to feed through the circuit network through back contact 50 of relay ZAR, and through back contact 44 of relay 3R for the energization of other switch control relays for trailed track switches; however, the designation of an exit point at signal A, in the example described above, does not feed energy in the circuit network past contacts 50 and 45 of relays 2AR and 3R respectively because those relays have already been picked up responsive to the designation of an entrance point at signal E.

After having considered the principles involved in setting up routes in which the reverse positions of the track switches are selected, it will now be pointed out how a very similar mode of operation is eifected when normal positions of the track switches are selected. A feature that the selection of the normal position for track switches has in common with the selection of a reverse position for track switches, is that, for a crossover, the energization of a normal switch control relay for each end of the crossover is required in order that the switch machine may be operated to a normal position and in order that a track switch of that particular crossover can be included in a normal position in the route selected by the system. One of the normal switch control relays for a crossover is responsive to the designation of the entrance point in setting up a route, and the other normal switch control relay for that crossover is responsive to the designation of an exit point in setting up a route. A much similar mode of operation is followed in selecting the normal position for a single track switch in setting up a route, namely, the normal switch control relay for that track switch is responsive to the designation of either an entrance or an exit point, dependent upon from which it is trailed, and a relay X for that single track switch is dependent for energization upon the designation of the opposite end of the route being set up,'the picking up of the relay X in combination with the relay N for the single track switch is used as an executing means for causing the operation of the track switch.

As an example of how a route is selected in which the normal position of a track switch is involved, assume, at a time when the normal conditions of the system exist as described, that an operator desires to set up a route from signal B to signal E. The depression of entrance button BNB for designation of the entrance point of the route, causes the picking up of relay BNR by the energization of a circuit similar to that described for the picking up of relay ANR, and such entrance relay is maintained picked up dependent upon the track relay STR maintained energized.

Responsive to the picking up of relay BNR, relay ZBN is picked up by the energization of a circuit closed from through a circuit including front contact 59 of relay BNR, back contact 60 of relay BXR, back contact SI of relay ZAR, and center winding of relay iBN, to Upon designation of the exit point at signal E by the depression of button EXR, relay EXR is picked up by the energization of a circuit closed from through a circuit including front contact 59 of relay BNR, back contact 60 of relay BXR, back contact SI of relay ZAR, front contact 36 of relay ZBN, back contact 31 of relay 3N, wire 49, winding of relay EXR, back contact 38 of relay ENR, and contact 39 of button EXB closed in a depressed position, to The picking up of relay EXR closes a stick circuit at front contact 40 for shunting contacts 38 and 39 out of the circuit just described.

Responsive to the picking up of relay EXR, relay 3B is picked up by the energization of a circuit which has been described, and the picking up of relay 3R closes a circuit for relay 3X extending from through a circuit including front contact 59 of relay BNR, back contact 68 of relay BXR, back contact 6| of relay ZAR, front contact 36 of relay ZBN, front contact 44 of relay 3B, and winding of relay 3X, to

The picking up of relay 3R causes the picking up of relay 2AN by the energization of a circuit closed from through a circuit including front contact 4! of relay EXR, wire 42, back contact 43 of relay 3N, front contact 45 of relay 3R, back contact 46 of relay 3N, front contact 41 of relay 2BN, and upper winding of relay 2AN, to The picking up of relay ZAN definitely determines that one of the track switches of crossover v2 is to be included in the route which has been definitely selected up to that point, and thus, with relays ZAN and 2BN picked up, the track switches of the crossover 2 are'operated to corresponding positions. It will be noted from the above described example, that, in setting up a route from signal B to signal E, relay 2BN is responsive to the designation of the entrance point, and relay 2AN is responsive to the designation of the exit point in setting up that route. If, however, the same route is setup for west bound traflic, that is, from signal E to signal B, relay 2BN is picked up responsive to the designation of the exit point when energy is applied to the circuit which has been described for that relay, and relay 2AN is picked up after relay "2BN is picked up, dependent upon energy fed through the circuit network extending from the entrance relay ENR.

, such a route at a time ditions of the system exist.

To consider in a more specific manner how the normal switch control relays are energized for crossover 2 in setting up a route from signal E to signal B, assume an operator to designate when the normal con- The designation of the entrance point at signal E causes the picking up of relay ENR, and the picking up of that relay causes the picking up of relay 3R by the energization of a circuit which has been described.

Upon designation of the exit point for that route by the depression of button BXB, relay BXR is picked up by the energization of a circuit closed from through a circuit includ-' 'ing front contact 53 of'relayENR, back contact 4| of relay EXR, wire 42, back contact 43 of relay 3N, front contact 45 of relay 3R, back contact 46 of relay 3N, back contact 62 of relay 2BR, winding of relay BXR, back contact 63 of relayBNR, and contact 64 of button BXB closed in a depressed position, to The picking up of relay BXR. closes a stick circuit for that relay at front contact 65 to shunt contacts 63 and 64 out of the circuit just described. 7

switches ontr l rel y s has IA to signal E. Under such conditions, relays After relay BXRv is. picked picked up when. tact fill to a circuit which -has been described. When relay. ZBN is picked up, relay VZoAN, is, picked'upby, theenergization of a. circuit closed from (-1-), througha, circuit, including front cone. tact 5310f, relayENR, back contact A! of; relay EXR, wire 42, back contact 43 of-relay 3N, front contact 450i relay 3R, back contact liter relay 3N, front contact 41 of relay, ZBN, and, upperv winding of relay ZAN. to.

It will-be noted that. in the. selection of a route which includes a track switch in a normal position, the selection of the track switches as, being,

definitely included in a, route selected.v betvireenv the entrance and exit pointsidesignated, is effectedin a cascade order, onetrack switch or one small groupof track switches at a time, starting up, relayr2BN: is. energy is. applied at front. con-1 with the track switch nearest the designated exit point the same as was pointed out in do scribing the setting up of routes including the track switches in their reversepositions.

lit is believed from the abovetypical examples and general descriptionof the mode of operation of the normal and reverseswitch control relays in selecting the various. routes, that it will be readily apparent to those familiar with the art how'the system can be expanded "to satisfy any particular track layout encountered in practice.

It will be pointed out, however, hereinafter, how;

the system satisfies particular conditions encountered in practice with respect to the selection of a preferred one of several optional routes.

Switch control-Although the normal and re-' verse switch controlrelays select theposit'cn to which their respective track switches, are to be operated, as has been pointed out in a general manner, the normal and reverse switch control relaysfor each track switch are not effective icr' causing the positioning. of that track switch unlesstherehas been a relay for that track switch energized in each of the two circuit networks forthat interlocked group, one relay being energized dependent upon the entrance point designated, and the other. relay being energized dependent upon the, exit point designated, it has also been pointed out that, in set-tingfup a route, the track switches, are selected, as being definitely determined to-be included in that route in succession, one track switch or one small group of track switches at atime, starting with the track switch nearest the designated exit point. Thus, if each of the track switches is operated to the selected position dependent upon both entrance and exit point designation, and the definite selection of a track switch is dependent upon the complete selection of the roll fl up to that track switch from the exit point designated, the track switches are initiated into operation in succession, one track switch or one small group of track at a time, starting with the track switch nearest the desi nat d it po nt Inasmu h as h sw h con r cir ar similar for the control of, each of the track witc s, the c ntr l ir i s h wn in Fig- 2 can be considered typical of the circuits provided for the control of each of the other switch machines. Thus, to consider the mode of operation of the typical switch control system as. shown in Fig. 2, assume, for example, that a route has been selected by the normal and reverse switch been described from signal ZAR and 235 am i l, Q91. elay 23 be n picked up responsive to the designation of the entrance point at signal A, andrelay ZARv being picked unresponsive to the designation of the exit point at signal E. 7

After relays ZAR and. 2BR, have both been picked up, assuming the prior position of the track switches of the crossover to be normal as 2W1 are operated to their left hand positions in correspondence with the reverse locked positions of the switch machine ZSM and the track switches 2TSA and ZTSB, thus opening thecircuit for the relay 2WZ and causing that relay to be dropped. away. The dropping away of relay 'ZWZdeenergizes the switch machine control c-ir cult, and. causes the picking up of a correspondence relay ZROR which repeats the reverse po-' sition or. the contacts of relay 2W? in correspondence with the picked up position of the reverse. switch control relays" 2A3, and 2BR. When relay2RCR is picked up, a branch of the circuit network for the control of the signal control relays G is closed to indicate that the track switches have. been properly positioned for the crossover 2-in the particularroute selected.

To consider. more specifically how the lays ZAR and conditions described: above, the lower winding of relay ZWZ is energized by a circuit closed from through a circuit including front contact 66 of relay ZAR,

provide. the energization. of an obvious circuit for operating the'switch machine ZSM to a reverse position.

When the switch machine has. completed its operation to a reverse position and the relay ZWP is picked upwith its polar contacts operated to a left hand position, relay ZWZ is dropped away because of the opening of polar contact 68 of relay 2WP in a right hand position. When relay ZWZ has dropped away, relay ZRCR is picked up by the energization of a circuit closed from (-1-), through a circuit including front contact 66 of relay 2AR, front coritact 61 of relay 2BR, polar contact 68 of relay ZWP in a lefthand position, front contact 13 of relay ZWP, back contact l4 of relay 2W2, and winding of relay 2RCR, to l'.'he control circuit for the switch'machine ZSMis of course opened at front contact'lZ of'relay 2W2 upon the nd t r n ente relay ZRCR s p ked up;

m ia y O QWmg heri lsine 1 o th e ond of the two reverse switch control relays for After v circuits provide such a modeof operation, assuming re 238. to be picked up under the front contact 6'! of relay 2BR, polar contact 63 of relay ZWP. in a right hand' position, front contact fill. of relay IL, front conthe correspondence that crossover, by the energization of the circuit just described for that relay.

To consider the circuits by which the switch machine ZSM is operated from a reverse posi- -tion to a normal position, assume the track switches ZTSA and ZTSB to be in their reverse locked position when the normal position of such track switches is selected by the picking up of relays ZAN and 2BN, as is effected in setting up a route from signal B to signal E. When relays ZAN and ZBN are picked up, relay ZWZ is picked up by the energization of a circuit closed from through a circuit including front contact 15 of relay 2AN, front Contact 16 of relay 2BN, polar contact 11 of relay ZWP closed in a left hand position, front contact 18 of relay 1L, front contact 19 of relay 8L, back contact 80.0f relay ZRCR, and upper winding of relay ZWZ, to When relay 2W2 is picked up responsive to the energization of that circuit, energy is applied to the switch machine 2SM at front contact 12 to cause the operation of that switch machine to a normal position in correspondence with the position selected by the normal switch control relays ZAN and 2BN, After the track switches ZTSA and ZTSB have been operated to their reverse positions and locked in correspondence with the switch machine 28M, the relay ZWP is picked up with its polar contacts operated to a right hand position, thus opening the pick-up circuit just described for relay 2WZ at polar contact 11 in a left hand position, to. cause relay ZWZ to be dropped away. Uponthe dropping away of relay ZWZ energy is removed from the switch machine control circuit and the correpondence relay ZNCR is picked up by the energization of a circuit closed from through a circuit including front contact 15 of relay ZAN, front contact it of relay 2BN, polar contact 11 of relay 2WP closed in a right hand position, front contact ill of relay ZWP, backv contact 82 of relay ZWZ, and winding of relay ZNCR, to The picking up of relay ZNCR closes the portion of the signal control circuit network associated with crossover 2 as is shown in Fig. 3 and hereinafter described.

If the track switches ZTSA and ZTSB are in their normal positions as shown when the normal position of such track switches is selected by the picking up of relays ZAN and. 2BN, relay ENCR will be energized upon the picking up of those relays because the pick-up circuit of relay 2W2 would be open under such conditions at polar contact 11 in a left hand position.

To provide that the track switches will complete their operation, once the operation of the switch machine is selected by the picked up position of relay 2WZ, when the normal position for those track switches is selected, even if the normal switch control relays 2AN and ZBN are dropped away prior to the completion ofthe operation, a stick circuit is provided for relay ZWZ, closed from through a circuit including front contact 83 of relay 2WZ, polar contact 84 of relay ZWZ closed in a right hand position, back contact 85 of relay 2BR, back contact 86'of relay ZAR, polar contact 11 of relay 2WP in a left hand position, front contact 18 of relay 1L, front contact 19 of relay 8L, back contact 80 of relay ZRCR, and upper winding of relay 2WZ, to

A stick circuit is also provided in order that the track switches ETSA and ZTSB will be operated to their reverse positions, when such control is selected by the relay 2WZ, irrespective of the position of relays 2AR and 2BR, closed from through a circuit including front contact 83 of relay ZWZ, polar contact 84 of relay 2WZ in a left hand position, back contact 81 of relay ZAN, back contact 88 of relay 2BN, polar contact 68 of relay 2WP in a right hand position, front contact 69' of relay 1L, front contact 10 of relay 3L, back contact 1| of relay ZNCR, and lower winding of relay 2WZ, to

Inorder that the track switches 2TSA and 2TSB can be biased to their positions last selected by the normal and reverse switch control relays, it is provided that, should the track switches ETSA and/or 2'ISB become unlocked from the positions previously selected by the relays 2AN and 2BN, relay ZWZ is picked up by the energization of a circuit closed from through a circuit including back contact 89 of relay ZWP, polar contact 84 of relay ZWZ' in a right hand position, back contact 85 of relay 233, back contact 86 of relay ZAR, polar contact 11 of relay 2WP in a right hand position, back contact iii of relay 2WP, front contact18 of relay 1L, front contact 19 of relay 8L, back contact 38 of relay ZRCR, and upper winding of relay 2WZ, to The picking up of relay 2W2 due to the energization of that circuit would cause the switch machine ZSM to be operated back to a normal locked position.

If the track switches 2TSA and ZTSB should become unlocked from their lastselected reverse position, relay 2WZ would be picked up to cause the switch machine 28M to be operated back to a reverse locked position, by the energization' of a circuit closed from (+),,through a circuit including back contact 89' of relay EWP, polar contact 84 of relay 2WZ in a lefthand position, back contact 81 of relay ZAN, back contact 88 of relay 2BN, polar contact 68 of relay 2WP in a left hand position, back contact 13 of relay ZWP, front contact 69 of relay 1L, front contact 10 of relay 8L, back contact 1! of relay ZNCR', and lower winding of relay 2W2, to t It is believed that it will be obvious from the above described circuits that, if a track switch is moved, for example, from its normal position to its reverse position by a maintainer hand. cranking the switch machine 23M, the dropping away of the relay EWP during such operation causes the picking up of relay ZWZ as has been described, and the closing of the stick circuit for relay ZWZ at front contact 83 which is connected in multiple with back contact 69 of relay 2WP, provides that, whenever the power operation of the switch machine is rendered efiective by the closing of the crank contact. in the switch machine by the maintainer, the switch machine ZSM will be operated back to its normal position by power operation, even if it has been hand cranked to a reverse locked position to cause the picking up of relay ZWP. It is believed that it will be obvious that a similar mode of operation is effected whereby the track switch can be restored to a reverse position if such position has been selected prior to the hand cranking of the switch machine 28M to a normal position.

In addition to the control of the normal and reverse switch control relays, responsive to the designation of the ends of each route, it is provided that the track switches for each crossover and each single track switch can also be positioned by actuation of an auxiliary switch control lever SML for that particular crossover or single track switch. Thus, the relays 2AN, 2BN,

control lever 2SML. If an operator desires to cause the operation of the track switches ZTSA and 2TSB to a normal or a reverse position, by positioning the auxiliary switch control lever ZSML; he can cause such operation by actuating I that lever from the normal center position to an upper or a lower operating position in accordance with the-normal or reverse position desired for the track switches 2TSA and ZTSB.

' To consider an example of how a track switch can'be positioned by the operation of the control lever ZSML, assume that an operator moves the lever 2SML to a reverse operating position, at a time when the normal conditions of the system exist as have been described. Such operation causes the contacts associated with lever ZSML to be operated to a left hand position to close acircuit for causing the picking up of relay 2AR, irom through a circuit including contact 90 of lever 2SML closed in a left hand position, back contact 9| of relay 2AN, back contact 92 of relay -2BN, and lower winding of relay 2AR, to Upon the picking up of relay 2AR, relay 2BR is picked up by the energization of a circuit closed from through a circuit including contact 90 of lever 2SML closed in a left hand position, back contact 9| of relay 2AN, back contact 92 of relay 2BN,- front contact 93 of relay ZAR, and lower winding of relay 2BR, to In accordance with the picking up of relays ZAR- and 2BR, the switch machine-2SM is operated to a reverse position in the same manner as has been described.

If, when the track switches ZTSA and ZTSB are reverse, an operator moves the lever ZSML to a normal operating position to cause the contacts associated with that lever to be operated to the right, relay 2AN is picked up by the energization of a circuit closed from through a circuit including contact 90 of lever 2SML in a right handposition, back contact 94 of relay 2AR, back contact 95 of relay 2BR, and lower wind ing. of relay 2AN, to When relay 2AN is picked up, relay 2BN is picked up by the energization of a circuit closed from through a circuit including contact 90 of lever 2SML in a right hand position, back contact 94 of relay ZAR, back contact 95 of relay 2BR, front contact 96 of relay 2AN, and lower winding of relay 2BN, to Responsive to the picking up of relays 2AN and 2BN, the switch machine 28M is operated to a normal position in the same H manner as has been described.

If, for some reason, such as obstruction at the switch points, the operation of a track switch cannot be completed after the switch machine has been set into operation, an operator can cause the restoration of that track switch to its former position. bycausing the energization of the switch control relays for the corresponding desired position of that track switch. That is, for example, if the relays ZAR and 2BR have been picked up and the switch machine ZSM has been partially operated from its normal to its reverse position and the complete operation of that switchmachine is obstructed, an operator, upon causing the dropping away of relays 2A3 and 2BR and the picking up of relays 2AN and ZBN, can cause the switch machine 23M toj be restored to its original normal position. Such operation is effected because the picking up of the relays 2AN and 2BN opens the stick circuit described for relay 2WZ at back contacts 81 and Y feature 88 respectively, thus allowing relay 2W2 to be dropped away andenergized with the opposite polarity in accordance with the normal switch control relays 2AN and ZBN picked up.

If it is not required in practice that the bias of the switch control circuits be provided, back contact 89 of relay 2WP can be eliminated and back contacts 81, '88, 86 and of relays 2AN, 2BN, ZAR and'2BR respectively are no longer required in the stick circuits for relay 2WZ, because reversal in midstroke can then be accomplished by causing relay 2WZ to be dropped away upon energization of bothwindings with opposite polarity. Upon the dropping away of the relay 2WZ, under such conditions, the winding energized in the stick circuit of the relay 2WZ is deenergized, thus causing the polar contacts to be operated to the opposite position and the relay to be picked up for causing the operation of the switch machine back to its former locked position.

In Fig. 6 of the accompanying drawings, a typical single switch control circuit is shown for the track switch 3TS of the track layout shown in Fig. 3. The control circuits shown in this Fig. 6 are similar to those shown in Fig. 2 and their operation will not be described in detail. It is noted that the lock relay 8L is controlled by the directional stick relays 8E8, 8TB and 8W8 by contacts 239, 23l and 232 respectively, in a similar manner as the lock relay 8L'of Fig. 2 is controlled through contacts 26, 25 and 24 of the same relays. The lock relay 8L .is provided with a stick contact 293 which is used to shunt out the lever contact 234 of the lever 3SML.

The operation of the lever tSML, of course, operates .its contact 235 to either the normal or the reverse position to energize the corresponding normal or reverse control relay 3N or 3R. The picking up of the normal control relay;3N or the reverse control relay 3R. upon the operation of the lever 3SML passes energy on to the execution relay 3X to energize it. The energization of this exit relay 3X then completes the normal or reverse control circuit as selected by the particular normal or reverse control relay 3N or 3B then picked up. It is, of course, understood that the execution relay 3X is also picked up with either the normal or the reverse control relay through the medium of the selecting circuits as shown and described in connection with Figs. 1A and 13. It is believed that further operation of the'circuits shown in Fig. 6 will be obvious from the consideration of the drawings in View of the description given in con,- nection with Fig. 2.

Signal controls-The signal control relays C- which govern the indication of the signals are energized by a signal control circuit network as is shown, for example, in Fig. 3 for the track layout illustrated in that figure. The same circuit network is used for energizing signal control relays for controlling west bound traffic as is used for energizing signal control relays for east bound trafid' As a typical example of'the means by which eachfof the signal control relays G is energized, consider, for example, that a route has been selected from signal A to signal E and that the track switches ZTSA, ZTSB and 3TS have been properly positioned for that route. When the track switches 2TSA and ZTSB have been positioned for that route the correspondence relay ZRCR is picked up, and when the track switch 3738 has -been positioned for thatroute the correspondence relay 3RCR is picked up. The picking up of relay 2RCR closes the circuit for the signal control relay AG, .from (-1-), through a circuit including front contact 9?- of relay EXR, front contact 98 of relay 3RCR, back contact 99 of relay 3NCR, front contact Hill-of relay ZRCR, back contact Hil of relay ZNCR, back contact I92 of-relay AXR, front contact N3 of relay ANR, and winding of relay AG, to The picking up of relay AG opens back contact I04 to cause the red lamp in signal A to be extinguished and closes. front contact IM to cause the green lamp in signal A to be illuminated. M

It is believed thatit. will be obvious that the signal control relay EG can be. picked up, after a route is set up from. signal E to signal A by .the energization of a circuit includingthe same contacts of the correspondence relays as were. described as being included inthe control circuit for relay AG, energy being supplied under such conditions by front contact I82 of relay AXR.

To consider as another typical example how the signal. control relays G are controlled, assume that a route has been selected as heretofore described from signal B to signal E, and that the track switches have been positioned in accordance with their required positions for such route. The picking up of relay ZNCR, after the track switchesZTSA and 2TSB have been operated to their normal locked positions,.causes the picking up of relay BG by theenergization of acircuit closed from through a. circuit including front contact 9'! of relay EXR front contact 98 of relay 3RCR, back contact 99 of relay 3NCR, back contact. I06 of. relay ZRCR, front contact H35 of relay 2NCR,back contact Hit of relay BXR, front contact lfl'l of relay BNR, and winding of relay BG, to The opening of back contact I 08 of relay BG causes the extinguishing of the red lamp in signal B, and the closing of front contact I08 causes the illumination of the green lamp in signal vB.

Restoration to normal.nce the route establishing means is energized for setting up a route, it is maintained energized as long as theentrance relay for the entrance to that route is maintained picked up. Each of the entrance relays is maintained energized dependent for deenergization upon passage of a train passed the signal at that entrance point, or dependent for deenergization uponthe pulling out of the. entrance button NB forrthat particular entrance point. Other means dependent upon the route locking is provided for maintaining the route establishing means. efiective for the portion of each route in advance of each trainafter that train accepts the entering signal to that route in a manner which is hereinafter described when considering more in detail the route locking provided and the means provided for. the prevention of the preconditioning of routes.

To. consideras a specific example of how the route establishing means is restored to normal responsiv to manual control, assume an operator to initiate the restoration of the routeestablishing means for a route which has been set up .from signal A to signal E.

Upon the pulling out of button ANB, under such conditions (see Fig. 1A), relay ANR is dropped away by th opening of normally closedcontact 28.. When. relay ANR is dropped away, relay. .EXR. is. dropped. away .because of the opening of front contact 3| of relay ANR, and at the sam time the signal control.

for the relays IL and 8L. The pick-up circuit for relay 1L isclosed from (-1-), through a circuit including front contact 26 of relay IWS, front contact 21- of relay lTR, front contact 22 of relay YES, winding .of relay 7L, and contact Hi9 of lever ESML in a normal position, to The picking upof relay lLcloses a stick circuit for that relay at front contact 23 to provide the restoration of that relay to the normal conditions as have been described. The relay 3L is picked up by the energization of a pick-up circuit provided in a similar manner to the pick-up circuit just described. for relay IL.

The pick-up circuit for relay 2BR. is opened at front. contact. 3| of relay ANR when that relay is dropped away, and the dropping away of relay EXR opens the pick-up circuit for relays 3R and EAR at front contact 4| (see Fig. 1B) After such pick-up circuitsfor the relays 2BR, ZAR and 338. are openecLthose relays are dropped away as soon as the lock relays L for those track switches have been picked up to open stick. circuits hereinafter described for such reverseswitch control relays.

Th correspondence relays ZRCR and SRCR (seev Fig. 3) are dropped away, responsive to the dropping away of the reverse switch control relays for their associated track switches. Relay ZRCR is dropped away by the opening of front contacts 66 and 6'! of relays ZAR and 2BR respectively (see Fig. 2).

In a similar manner the route establishing means associated with each of the various routes can. be restored to normal at the will of an operator by the pulling out of the button for the entrance point to that particular route.

If the route establishing means for the route from signal A to signal E is to be automatically restored. upon passage of a train, a similar mode of operation to that justdescribed is effected. The entrance relay NR for the entrance point to that route is dropped away when the train passes the signal because of the opening of the stick circuit for that relay at front contact 29 of relay 'ITR (see Fig. 1A), and the pick-up circuits for the reverse switch control relays are opened in the same manner as has been described, but the reverse switch control relays are maintained picked up by their stick circuits until the detector track sections for those track switches become unoccupied in the rear of the passing train. The means by which such stick circuits are provided will be hereinafter described more in detail when considering the means provided for the prevention of the preconditioning of routes.

Route lockinl-Inasmuch as this invention is more particularly related to the novel features provided by the route selecting and route establishing means, it is believed to be unnecessary to show and describe the details of the circuits by which route locking and approach locking can be provided for the system shown, as is shown in the patent to A. Langdon, Patent No. 2,148,885, dated February 28, 1939, for the detailed circuits of a system of route locking that can be used with th system provided by the present invention. If, in addition .to.the.route.locking, approach locking is I required, the approach androute locking can be manner, for example,,such as is patent to C. F. Stoltz, Patent No.

provided in a shown in the z,1i5,51l, dated April 26, 1938.

The directional stick relays ES and WS used in this disclosure are comparable to the relays bearing similar nomenclature as shown in the tracksection for a particular direction of trafiic,.

and it is dropped away upon setting up a route through that track section in the particular di-' rection for which that route locking relay is provided. The general arrangement of the circuits is such that a route locking relay is dropped away for each track section included in a route estab-. lished in advance of a train, for that particular direction, and the route locking relays are picked up for the track sections as they become unoccupied in the rear of a train.

Prevention of p'reconditioning.-Once a route has been completely set up through a track layout, it is impossible to set up a route conflicting with the route already established, and further-, more, it is impossible to so condition that con--: flicting route that it will be set up automatically as soon as that route is made available by the. restoration of the conflicting route previously established. Such mode of operation is desirable in practice particularly in order that the momentary loss of shunt of a track relay cannot cause the operation of a track switch under a train to a position other than the position required for the route established.

To consider an example of how the preven-'- tion of the setting up of conflicting routes, and the prevention of the preconditioning of routes is accomplished, assume set up as has been described from signal A to' signal E (see Figs. 1A and 1B), and also consider that, after the route is established from signal A to signal E, an operator designates signal B as an entrance point for a conflicting routefrom signal B to signal D. The designation of signal B as an entrance point causes the picking up of the entrance relay BNR, and the picking up of that relay closes front contact 59 to cause energy to be applied to the circuit network to feed through the network toward the exit relay DXR which must be picked up responsive to the designation of an exit point if the route or any track switch in the route is to be completely selected. Relay DXR cannot be picked up, however, because energy can feed from front contact 59 of relay BNR. through the circuit network only so far as back contacts 6| and I it of relays ZAR and 2BR respectively, because those relays are picked up at that time to correspond with the route set up from signal A to signal E. Thus, it is not only impossible to complete the selection of the conflicting route from signal B to signal D, but it is further provided that the switch control relays ZAN and ZBN cannot be conditioned for crossover 2, and the relay 3N cannot be conditioned for track switch 3, for the route from signal B to signal D, because the circuit for relay 2BN is opened at back contacts BI and IIO.of relays ZAR and 2BR, the circuit for relay 2AN and the circuit for relay 3N are held open because of the failure of relay Dim to be picked up responsive to the designation of the exit point-at signal D to close front. contact I28 of that relay and feed energy that a route has been 'vides the same means through the circuit network toward the relays 3N and ZAN.

It is, of course, desirable to maintain such means for prevention of preconditioning of the route from signal B to signal D as long as a portion of that route conflicts with a route maintained established, by the route locking, thus, when a train accepts signal A, in proceeding through the route set up from signal A to signal E, it is provided that the reverse relays ZAR and 2BR. are maintained picked up because that crossover has its track switches maintained locked by the detector and route locking. Inas: much as the normal and reverse switch control relays are maintained energized, dependent upon the locked condition of the trackswitches, the picked up position of the relays 2AR and 2BR as maintained by the presence of the train in track section IT and in track ssection 8T profor the prevention of. the preconditioning of a conflicting route by holding open contacts BI and III] of relays 2A3 and 2BR respectively as has just been described. c

To consider the circuits in detail bywhich the relays ZAR and 2BR are maintained picked up dependent upon the electric looking, with reference to Fig. 2, assume a route has been set up from signal A to signal E and the entering signal A has been cleared. The clearing of signal A causes the dropping away of the relays IL and 8L because of the dropping away of relays IE5 and BES to open respectively front contacts 22 and 26. When relay IL is dropped away, a stick circuit is closed for relay 2BR from through a circuit including back contact H2 of relay IL, front contact H3 of relay 2BR, and lower winding of relay 2BR, to A stick circuit is also closed at that time for relay ZAR from through a circuit including back contact IIZ of relay IL, front contact H3 of relay 2BR, front contact 93 of relay ZAR, and lower winding of relay ZAR, to The dropping away of relay 8L closes back contact II4 to supply energy to those stick circuits in multiple with back contact II2 of relay IL, thus, when relay IL is picked up as the section IT is released in the rear of the train, the stick circuits for relays ZAR and 2BR are still maintained energized by back contact H4 of relay 8L. As the trainleaves track section 8T, the picking up of relay 8L releases the stick circuits for relays 2AR. and 2BR by opening back contact M4 to cause those relays to drop away, and thus allow the crossover 2 to have its track switches positioned in accordance with the next route in which those track switches are to be included.

In a similar manner, the relays 2AN and ZBN are maintained picked up dependent upon the locked condition of the track switches ZTSA and ZTSB. When a signal has been cleared for a route including the track switches ZTSA and 2TSB in normal positions, and. the route locking has become effective, a stick circuit is closed for relay '2BN, from through a circuit including either back contact II2 of relay IL or back contact II4 of relay 8L, as the case may be, front contact I49 of relay ZBN, and lower winding of relay ZBN, to At the same time a stick circuit is closed for relay 2AN, from through a circuit including back contact II2 of relay IL, or back contact II I of relay 8L, as the case may be, front contact I49 of relay ZBN, front contact 96 of relay ZAN, and lower winding of relay ZAN, to 

